Sony’s PlayStation Network was taken offline for several hours on Sunday by a distributed denial-of-service (DDoS) attack.

The attack appeared to be part of a campaign that also affected other online gaming networks, including Blizzard’s Battle.net, Grinding Gear Games and Microsoft’s Xbox Live.

Bomb scare

The incident took an unusual turn when a Twitter user named “LizardSquad”, which had claimed responsibility for the attack, began posting comments related to Iraq’s ISIS and the “Islamic State”, and tweeted that there might be “explosives” on board a plane carrying a Sony executive. The flight from Dallas to San Francisco was diverted to Phoenix, Arizona.

“Yes, my plane was diverted. Not going to discuss more than that. Justice will find these guys,” wrote John Smedley, president of Sony Online Entertainment, in a Twitter post.

Smedley had mentioned a “large-scale DDoS” on Twitter before tweeting that he was about to board the plane.

He later downplayed the incident, writing on Twitter that the bomb warning had come from “DDoS trolls” who shouldn’t be “taken seriously”. A Sony representative said the incident was being investigated by the FBI.

Service issues

“LizardSquad” had earlier said the cyber-attacks were intended to demonstrate the weakness of networks such as Sony’s.

“Multi-million dollar companies aren’t spending your money to ensure your game has good service,” said a message posted on the account. A rival hacker associated with the Anonymous group has also claimed responsibility for the attacks.

As of Sunday, Sony said normal service had been restored to the PlayStation Network, while Microsoft and Blizzard continued to report problems.

“We’ve recently been experiencing DDoS attacks and have been working to improve stability across Battle.net services,” a Blizzard representative stated in the company’s technical support forum on Sunday night.

Microsoft declined to comment on the “root cause” of the service problems, but acknowledged “server unavailability issues” in a message on its Xbox support site.

Grinding Gear Games also acknowledged “server issues due to a DDoS attack” on the Twitter account for its Path of Exile game on Sunday.

No ‘intrusion’

Sony sought to reassure users that the incident is not a repeat of a 2011 compromise which saw 77 million members’ personal details compromised.

“We have seen no evidence of any intrusion to the network and no evidence of any unauthorized access to users’ personal information,” said Sony social media manager Sid Shuman in a blog post.

Blizzard was hit by a DDoS attack in Europe earlier this year. And back in 2011, the Playstation Network suffered a huge breach which took it offline for a week, and led to the possible compromise of 77 million users’ credit card details.